The present invention relates generally to switch mode power control systems. More particularly, the present invention relates to a power supply architecture for controlling and monitoring a plurality of independent and isolated output modules such as point-of-load regulators.
Point-of-load power conversion systems have become increasingly popular for use in contemporary power supply architectures. An electronic system may commonly require power to be provided at different discrete voltage and current levels, including for example circuits which may require a relatively low voltage (e.g., 1 V) but with relatively high current (e.g., 100 A). It is generally considered undesirable to deliver relatively high current at low voltages over a relatively long distance through an electronic device, as power distribution losses may become prohibitive. For example, to maintain constant distribution efficiency the bus cross-section in typical centralized architectures may need to be increased exponentially with respect to the reduction in voltage.
Typically, an intermediate bus voltage converter may be used to provide an isolated intermediate bus voltage (e.g., 9 V) from a relatively higher nominal input voltage source (e.g., 48 V). This intermediate bus voltage may be distributed throughout the power system for further point-of-load power conversion. If the input voltage source is regulated, the intermediate bus voltage converter can be unregulated. A conventional intermediate bus voltage converter includes a transformer to provide isolation between the input and output voltages. On the output side of the transformer, synchronous rectifiers convert the periodic voltage on the transformer to a DC output voltage.
The point-of-load power conversion of the intermediate bus voltage may typically be carried out by individual point-of-load (“POL”) regulators, i.e., a DC/DC converter at the point of power consumption. A power system may include a plurality of POL regulators to convert the intermediate bus voltage into each of the plurality of required power levels. Ideally, each POL regulator would be physically located adjacent the corresponding load so as to minimize the length of the low voltage, high current lines through the power system. The intermediate bus voltage can be delivered to the plurality of POL regulators using low current lines that minimize losses.
In point-of-load power conversion systems, it is further known to provide a power system controller which is adapted to activate, control and monitor the plurality of POL regulators via a multi-connection parallel bus. Such control systems often however introduce undesirable complexity and size to the overall power system.
Further, most conventional point-of-load power conversion systems provide non-isolated POL regulators, predominantly due to their lower cost. However, non-isolated POL regulators may expose loads which are particularly sensitive to over-voltage conditions, and ground loop conditions are also a potential problem for the power system as a whole.